A motorcyclist heading east through a small Iowa town accelerates after he passes a signpost at x=0 marking the city limits. His acceleration is constant (4.0 m/s2). At time t =0 he is 5 m east of the signpost and has a velocity of 15 m/s. (a) find his position and velocity at time t=2 sec. (b) where is the motor cyclist when his velocity is 25 m/s?

Respuesta :

Answer:

a) 43 m b) 55 m

Step-by-step explanation:

a) From question at t = 0, initial velocity [tex]V_{o}[/tex] = 15 m/s

   Using equation of motion, [tex]S = V_{o}t + \frac{1}{2} at^{2}[/tex] ; at t = 2 secs , a = 4 m/[tex]s^{2}[/tex]

    S = (15 x 2) + (0.5 X 4 x [tex]2^{2}[/tex])

    S = 30 + 8 = 38 m , Therefroe;

  car is (38 + 5)m from the sign post

  car is 43 m from the sign post at t = 2 secs

b) Also from equation of motion, [tex]V^{2} = V_{o} ^{2} + 2aS[/tex]

    [tex]25^{2} = 15^{2}[/tex] + (2 x 4 x S)

     625 - 225 = 8S

S = 50 m

 Car is (50 + 5) m from the sign post

Car is 55 m from the sign post at V = 25 m/s